The present application relates generally to electrosurgical systems and methods and more particularly relates to electrosurgical generators and advanced bipolar electrosurgical devices or instruments.
Electrosurgical devices or instruments have become available that use electrical energy to perform certain surgical tasks. Typically, electrosurgical instruments are hand tools such as graspers, scissors, tweezers, blades, needles, and other hand tools that include one or more electrodes that are configured to be supplied with electrical energy from an electrosurgical generator including a power supply. The electrical energy can be used to coagulate, fuse, or cut tissue to which it is applied.
Electrosurgical instruments typically fall within two classifications: monopolar and bipolar. In monopolar instruments, electrical energy is supplied to one or more electrodes on the instrument with high current density while a separate return electrode is electrically coupled to a patient and is often designed to minimize current density. Monopolar electrosurgical instruments can be useful in certain procedures, but can include a risk of certain types of patient injuries such as electrical burns often at least partially attributable to functioning of the return electrode. In bipolar electrosurgical instruments, one or more electrodes is electrically coupled to a source of electrical energy of a first polarity and one or more other electrodes is electrically coupled to a source of electrical energy of a second polarity opposite the first polarity. Thus, bipolar electrosurgical instruments, which operate without separate return electrodes, can deliver electrical signals to a focused tissue area with reduced risks.
Even with the relatively focused surgical effects of bipolar electrosurgical instruments, however, surgical outcomes are often highly dependent on surgeon skill. For example, thermal tissue damage and necrosis can occur in instances where electrical energy is delivered for a relatively long duration or where a relatively high-powered electrical signal is delivered even for a short duration. The rate at which a tissue will achieve the desired coagulation or cutting effect upon the application of electrical energy varies based on the tissue type and can also vary based on pressure applied to the tissue by an electrosurgical instrument. However, even for a highly experienced surgeon, it can be difficult for a surgeon to assess how quickly a mass of combined tissue types grasped in an electrosurgical instrument will be fused a desirable amount.
Attempts have been made to reduce the risk of tissue damage during electrosurgical procedures. For example, previous electrosurgical systems have included generators that monitor an ohmic resistance or tissue temperature during the electrosurgical procedure, and terminated electrical energy once a predetermined point was reached. However, these systems have had shortcomings in that they can provide inconsistent results at determining tissue coagulation, fusion, or cutting endpoints for varied tissue types or combined tissue masses. These systems can also fail to provide consistent electrosurgical results among use of different instruments having different instrument and electrode geometries. Typically, even where the change is a relatively minor upgrade to instrument geometry during a product's lifespan, the electrosurgical generator must be recalibrated for each instrument type to be used, a costly, time consuming procedure which can undesirably remove an electrosurgical generator from service.